1. Field of the Invention
This invention relates to a crystalline alumino-silicate catalyst having added silica contained within its interior structure, the manufacture of such catalyst and use thereof in the selective conversion of low molecular weight monohydric alcohols or ethers to light olefins.
2. Description of the Prior Art
U.S. Pat. No. 2,722,504 describes a catalyst of an activated oxide such as silica gel having a thin layer of an organosilicone polymer deposited thereon to increase the organophilic character of the contact surface and, as such, seeks to avoid silica deposition.
Crystalline aluminosilicate zeolites, modified by reaction with an organic substituted silane, have been described in U.S. Pat. No. 3,682,996 to Kerr and in U.S. Pat. No. 3,698,157 to Allen et al. The former of these patents describes, as novel compositions of matter, crystalline aluminosilicate esters made by reacting a crystalline aluminosilicate having an available hydrogen atom with an organic silane having a SiH group. The resulting compositions were disclosed as being catalysts useful for hydrocarbon processes, particularly hydrocracking. In the latter of the above patents, the use of ZSM-5 type crystalline aluminosilicate zeolites, modified by treatment with an organic-radical substituted silane are described, together with the use of such modified zeolites in chromotographic separation of the compounds contained in a C.sub.8 aromatic feed stock.
While the above-noted prior art is considered of interest in connection with the subject matter of the present invention, the catalyst, its manufacture and use in selectively producing low molecular weight olefins described herein has not, insofar as is known, been heretofore disclosed.
Low molecular weight olefins, i.e., ethylene and propylene, produced in accordance with the process described herein are valuable hydrocarbons and constitute building blocks from which many other commercially useful products can be manufactured.